Method and device for controlling welding hot cracking during welding by performing electromagnetic induction heating

Abstract

The invention relates to a method and device for controlling welding hot cracking during welding by performing electromagnetic induction heating. A preheating coil for preheating a workpiece to be welded is arranged in front of a welding gun; an after heating coil for heating a quickly-cooled welding seam for realizing slow cooling is arranged behind the welding gun; and the center of the after heating coil is positioned between positions which are in the center of a welding pool for the workpiece to be welded and are L1 and L2 distances away from corresponding positions of the upper limit temperature T1 and lower limit temperature T2 of the brittleness temperature rang TB of a welding material. In the invention, preheating before welding and slow cooling after welding are realized, so that the strain rate of the welding seam in the brittleness temperature rang is reduced, and welding hot cracking is controlled effectively on the aspects of metallurgy and mechanics; and moreover, the device has a simple structure, high production efficiency and low cost, is easy to realize, and contributes to energy saving and environmental protection.

Description

technical field [0001] The invention relates to a method and a device for controlling welding thermal cracks during welding, in particular to a method and a device for controlling welding thermal cracks by using an electromagnetic induction heating method, and belongs to the field of welding technology. Background technique [0002] Welding hot crack is a common problem in the welding process and is the main defect of welded components. Welding hot cracks mainly refer to the cracks generated when the weld and heat-affected zone metal cool to the high temperature zone near the solidus during the welding process, among which crystal cracks are the most common. Crystalline cracks only exist on the weld, and one is distributed longitudinally on the centerline of the weld, or distributed on both sides of the centerline in an arc shape. These cracks are distributed along the grain boundaries of primary crystallization, especially columnar crystals, crystallization cracks Mainly c...

AI Technical Summary

Problems solved by technology

For example, the static temperature difference stretching method requires a long heating time to achieve the required temperature difference, which is likely to cause softening of the metal in the heating zone, resulting in low production efficiency and high production costs.

Dynamic temperature difference stretching method, if water spray cooling will pollute the weld pool, resulting in weld defects, affecting the quality of welded joints, and flexible contact cooling with liquid nitrogen will lead to high costs

Rolling method with welding, complex equipment, high manufacturing cost, strict requirements on the shape of the workpiece to be welded, and the rolling wheel is easy to interfere with the welding torch to cause arcing

The impact rolling method with welding is only suitable for thin plate welding, and the energy cannot be precisely controlled, and with the changes in welding specifications and welding materials, the size of the impact rolling wheel needs to be redesigned and prepared

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